JP5003018B2 - Jet generator - Google Patents

Description

  The present invention relates to a jet generating device that generates a synthetic jet of gas, an electronic device equipped with the jet generating device, a drive signal generating device and a control device used in the jet generating device.

  Conventionally, an increase in the amount of heat generated from a heating element such as an IC (Integrated Circuit) associated with high performance of a PC (Personal Computer) has been a problem, and various heat radiation technologies have been proposed or commercialized. Yes.

  As a heat dissipation method, a composite jet is generated by discharging air in a pulsating flow, and this combined jet is supplied to a heat dissipation fin (heat sink), etc., and the temperature boundary layer formed on the surface of the heat dissipation fin is efficient. There is a method of well destroying and dissipating heat (see, for example, Patent Document 1). Such a jet generating device has a housing having an opening and a diaphragm that causes a pressure change in the air in the housing. When the diaphragm vibrates, a pressure change occurs in the casing, and air is discharged as a pulsating flow through the opening, thereby generating a synthetic jet.

  The synthetic jet is generated according to the following principle. As air flows when air is discharged from the opening of the housing, the air pressure around the opening outside the housing is reduced, so that the surrounding air is caught in the air discharged from the opening. A synthetic jet is generated.

Moreover, since the jet flow generator described in Patent Document 1 alternately discharges air from the two chambers, that is, discharges air in opposite phases, sounds generated from the respective chambers and openings (nozzles) weaken each other. This reduces noise.
Japanese Patent Laying-Open No. 2005-256834 (paragraph [0079], FIG. 1)

  However, in many cases, the sound generated from each chamber or opening of such a jet flow generating device does not actually become an accurate sine wave. This is because, for example, the amplitude waveform of the diaphragm may be distorted due to the shape or structure of an elastic support member that supports the driving device or the diaphragm. Therefore, it is difficult to dramatically reduce noise even when the diaphragm is driven in the opposite phase as described above.

In view of the circumstances as described above, an object of the present invention is to provide a jet flow generating equipment capable of achieving further noise reduction.

In order to achieve the above object, a jet flow generating apparatus according to the present invention includes:
A plurality of chambers each having an opening and containing a gas;
A vibrator that alternately discharges the gas as a pulsating flow through the openings by applying a pressure change to the gas contained in the chambers;
A correction wave signal generator for generating a correction wave signal in which a fundamental wave signal for driving the vibrating body is corrected ;
When the vibrating body is driven by the fundamental wave signal, when the amplitude center of the vibrating body is shifted from the origin position which is the initial position of the vibrating body, the correction wave signal generator A drive signal is generated as the correction wave signal so that the amplitude in one direction is different from the amplitude in the direction opposite to the one direction so that the amplitude center of the vibrating body and the origin position are the same.

In the present invention, the correction wave signal generator generates a correction wave signal in which the fundamental wave signal is corrected, and the vibrator is driven by the correction wave signal. Thereby, the amplitude waveform of a vibrating body becomes a suitable shape, and further noise reduction is realizable. In addition, for example, the initial center position in the vibration direction of the vibrating body (the origin position in the stationary state of the vibrating body) and the amplitude center position of the vibrating body can be made the same, and the amplitude can be Can be made symmetrical. The correction wave signal generator may level shift a signal for a time length smaller than one wavelength.

  Examples of the “gas” include air, but are not limited thereto, and may be nitrogen, helium gas, argon gas, or other gas.

  Examples of the driving method of the vibrating body include a method using an electromagnetic action, an electrostatic action, or a piezoelectric action.

  In the present invention, the correction wave signal generator includes a fundamental wave signal generation circuit that generates the fundamental wave signal, and a correction circuit that corrects the fundamental wave signal generated by the fundamental wave signal generation circuit. In the case of the present invention, the drive signal generator can be realized by an analog processing circuit, for example. However, it is not necessarily limited to an analog processing circuit, and may be a digital processing circuit.

  In the present invention, the correction wave signal generator has a correction wave signal generation circuit for generating a correction wave signal corrected in advance. In the case of the present invention, for example, a correction wave signal may be generated in advance at the manufacturing stage of the jet flow generating device. In the present invention, the drive signal generator can be realized by a digital processing circuit. However, an analog processing circuit is not necessarily limited to a digital processing circuit.

  In the present invention, the correction wave signal generator generates a drive signal in which distortion of an amplitude waveform is corrected as the correction wave signal. Thereby, the distortion of the vibration waveform of the vibrating body can be eliminated, and the vibrating body can be vibrated with a clean basic waveform.

  In the present invention, the correction wave signal generator corrects the fundamental wave signal so that the amplitude waveform of the vibrating body is an amplitude waveform obtained by combining at least two of a sine wave, a triangular wave, a rectangular wave, and a trapezoidal wave. can do.

  In the present invention, the correction wave signal generator generates a drive signal corrected so as to blunt the peak of the triangular wave as the correction wave signal. According to the configuration of the present invention, the peak value of the speed of the vibrating body can be lowered even when the amplitude is the same as compared with the case where the vibrating body is driven with a sine wave signal as a fundamental wave signal, for example. It has been found that the noise increases as the speed of the vibrating body increases. That is, according to the present invention, noise can be reduced compared to the case of driving the sine wave signal. Further, by correcting so that the peak of the triangular wave is dull, it is possible to suppress the occurrence of rapid acceleration.

  In the present invention, the correction wave signal generator generates the drive signal as a correction wave signal corrected in advance. Also in the present invention, as described above, a drive signal that is corrected so as to blunt the peak of the triangular wave may be generated in advance in the manufacturing stage of the jet flow generating device.

  In the present invention, the correction wave signal generator generates a drive signal corrected so as to blunt the peak of the sawtooth wave as the correction wave signal.

  In the present invention, the correction wave signal generator generates the drive signal as a correction wave signal corrected in advance. Also in the present invention, as described above, a drive signal corrected so as to blunt the peak of the sawtooth wave may be generated in advance at the manufacturing stage of the jet flow generating device.

  In the present invention, the jet flow generating device corrects the fundamental wave signal by the correction wave signal generator based on the detection signal from the movement state detection means for detecting the movement state of the vibrator and the movement state detection means. And a control means for generating the correction wave signal. In the present invention, it is possible to sequentially generate correction wave signals in real time by feedback control. Thereby, distortion of an amplitude waveform can be suppressed and noise can be reduced. In addition, since the vibrating body can be vibrated in the same motion state with a plurality of jet flow generators, variations in vibration specifications and the like can be suppressed.

  The control means can be realized by an analog circuit or a digital circuit. An analog circuit is preferable for improving responsiveness, and a digital circuit is preferable for reducing noise.

  “Based on the detection signal from the motion state detection means” means that, for example, the motion state detection means detects that the amplitude center of the vibrating body is deviated from the origin position or the amplitude waveform is distorted. In this case, it is “based” in the sense that the control means causes the correction wave signal signal generator to correct the drive signal so that the amplitude waveform becomes an ideal waveform, that is, a target waveform. Examples of the “ideal waveform” include a sine wave, a triangular wave, a sawtooth wave, and a rectangular wave. The same applies hereinafter.

  In the present invention, the jet flow generating device includes a movement state detection unit that detects a movement state of the vibrating body, and the correction wave signal that is corrected in advance based on a detection signal from the movement state detection unit by the correction wave signal generator. And a control means for generating. In the present invention, based on the detection signal from the motion state detection means, the fundamental wave signal is corrected in advance by the correction wave signal generator, and thereafter, feedforward control in which the vibrating body is driven by the correction wave signal is performed by open loop. It becomes possible. There are various possible timings for correcting the fundamental wave signal by the correction wave signal generator. For example, the timing may be a periodic timing, or may be a timing such as once or a plurality of times immediately after the jet flow generator is turned on. Alternatively, other timing may be used.

  In the present invention, the jet flow generation device includes a temperature detection unit that detects a temperature around the jet flow generation device, and the correction wave signal generator corrects the fundamental wave signal based on a detection signal from the temperature detection unit. Control means for generating the correction wave signal. “Ambient temperature of the jet generating device” refers to, for example, the temperature of the atmosphere around the casing, the temperature of the heating element to which the jet is applied, or the surrounding atmosphere and parts of the jet generating device, etc. Temperature. The same applies hereinafter.

  In the present invention, the jet flow generator includes a temperature detection unit that detects a temperature around the jet flow generation device, and the correction wave signal generator that corrects the correction wave signal that has been corrected in advance based on a detection signal from the motion state detection unit. And a control means for generating the above.

  A jet generator according to another aspect of the present invention has a plurality of chambers each having an opening, and a plurality of chambers containing gas, and applying a pressure change to the gas contained in each chamber, thereby pulsing the gas. And a drive signal generator for generating a drive signal corrected so as to blunt the peak of the triangular wave in order to drive the vibrator.

  In the present invention, for example, the peak value of the speed of the vibrating body can be reduced even when the amplitude is the same as when the vibrating body is driven by a sine wave signal. Further, by correcting so that the peak of the triangular wave is dull, it is possible to suppress the occurrence of rapid acceleration.

  According to still another aspect of the present invention, a jet generator includes a plurality of chambers each having an opening, and a plurality of chambers containing gas, and the gas contained in each of the chambers is subjected to a pressure change, thereby causing the gas to flow. A vibrating body that alternately discharges through the openings as a pulsating flow; and a drive signal generator that generates a driving signal that is corrected so as to dull the peak of the sawtooth to drive the vibrating body. .

  In the present invention, for example, the maximum value of the speed of the vibrating body can be lowered and the peak of the sawtooth wave is dulled even when the amplitude is the same as when the vibrating body is driven by a sine wave signal. By correcting in this way, it is possible to suppress the occurrence of rapid acceleration.

  According to still another aspect of the present invention, a jet generator includes a plurality of chambers each having an opening, and a plurality of chambers containing gas, and the gas contained in each of the chambers is subjected to a pressure change, thereby causing the gas to flow. A vibrator that alternately discharges through the openings as a pulsating flow, a movement state detection unit that detects a movement state of the vibration body, and a drive that drives the vibration body based on a detection signal from the movement state detection unit A drive signal generator for generating a signal.

  In the present invention, sequential drive signals can be generated in real time by feedback control based on the motion state of the vibrating body. Thereby, distortion of an amplitude waveform can be suppressed and noise can be reduced. Alternatively, even if it is not real time, for example, a drive signal is generated based on a detection signal from the motion state detection means at a certain timing, and then feed-forward control in which the vibrator is driven by the drive signal by an open loop is performed. Good.

  According to still another aspect of the present invention, a jet generator includes a plurality of chambers each having an opening, and a plurality of chambers containing gas, and the gas contained in each of the chambers is subjected to a pressure change, thereby causing the gas to flow. A vibrator that alternately discharges through the openings as a pulsating flow, a temperature detector that detects a temperature around the jet generator, and a drive that drives the vibrator based on a detection signal from the temperature detector A drive signal generator for generating a signal.

  In the present invention, it is possible to sequentially generate the drive signal in real time based on the temperature state around the jet flow generating device. Thereby, distortion of an amplitude waveform can be suppressed and noise can be reduced. Or even if it is not real time, a drive signal may be generated based on the detection signal by a temperature detection means, for example at a certain timing, and after that, an oscillating body may be driven with the drive signal by an open loop.

  According to still another aspect of the present invention, a jet generator includes a plurality of chambers each having an opening, and a plurality of chambers containing gas, and the gas contained in each of the chambers is subjected to a pressure change, thereby causing the gas to flow. A vibrating body that alternately discharges through the openings as a pulsating flow, and an external input interface that inputs a driving signal of the vibrating body from the outside of the jet generating device are provided. This is particularly effective when there are, for example, a plurality of jet generating apparatuses according to the present invention. For example, if one generator of the driving signal is prepared, the driving body of each of the jet generating devices is provided by inputting the driving signal of the one generator from the external input interface of the plurality of jet generating devices. Can be driven.

  In the present invention, the jet flow generating device further includes a signal generator that generates a second drive signal of the vibrating body, and a selector that selects one of the first and second drive signals. Thereby, each jet flow generator can be operated by combining a plurality of jet flow generators as mentioned above, and generating a drive signal by one of these signal generators.

  An electronic device according to the present invention has a heating element, a plurality of chambers each having an opening, and a plurality of chambers containing gas, and applying a pressure change to the gas contained in each chamber, thereby pulsating the gas. And a correction wave signal generator for generating a correction wave signal in which a fundamental wave signal for driving the vibration body is corrected, which is alternately discharged toward the heating element through the openings. .

  An electronic apparatus according to another aspect of the present invention includes a heating element, an opening, a plurality of chambers each containing gas, and a pressure change applied to the gas included in each chamber. A vibrator that alternately discharges gas toward the heating element through each opening as a pulsating flow, and a drive that generates a drive signal that is corrected so as to blunt the peak of the triangular wave to drive the vibrator. And a signal generator.

  An electronic apparatus according to still another aspect of the present invention includes a heating element, an opening, a plurality of chambers each containing gas, and a pressure change applied to the gas included in each chamber. A vibrating body that alternately discharges the gas as a pulsating flow toward the heating element through the openings, and a drive signal that is corrected so that the peak of the sawtooth wave is blunted to drive the vibrating body. And a drive signal generator.

  An electronic apparatus according to still another aspect of the present invention includes a heating element, an opening, a plurality of chambers each containing gas, and a pressure change applied to the gas included in each chamber. A vibrating body that alternately discharges the gas as a pulsating flow toward the heating element through the openings, a movement state detection unit that detects a movement state of the vibration body, and a detection signal from the movement state detection unit And a drive signal generator for generating a drive signal for driving the vibrating body.

  An electronic apparatus according to still another aspect of the present invention includes a heating element, an opening, a plurality of chambers each containing gas, and a pressure change applied to the gas included in each chamber. A vibrating body that alternately discharges the gas as a pulsating flow toward the heating element through the openings, a temperature detection unit that detects a temperature around the jet generation device, and a detection signal from the temperature detection unit And a drive signal generator for generating a drive signal for driving the vibrating body.

  The drive signal generator according to the present invention includes a plurality of chambers each having an opening, and a plurality of chambers each containing gas, and a pressure change applied to the gas included in each chamber, whereby the gas is used as a pulsating flow. A drive signal generating device for a jet generating device comprising a vibrating body that discharges alternately through each opening, and generating a correction wave signal that generates a correction wave signal in which a fundamental wave signal that drives the vibrating body is corrected And an amplifier for amplifying the correction wave signal generated by the correction wave signal generator.

  The control device according to the present invention has openings, each of which includes a plurality of chambers containing gas, and each of the openings using the gas as a pulsating flow by applying a pressure change to the gas contained in each of the chambers. A control device of a jet generating device comprising a vibrating body that is alternately discharged via a motion state detecting means for detecting a motion state of the vibrator, and the vibration based on a detection signal from the motion state detecting means A drive signal generator for generating a drive signal for driving the body.

  A control device according to another aspect of the present invention includes a temperature detection unit that detects a temperature around the jet flow generation device, and a drive that generates a drive signal that drives the vibrating body based on a detection signal from the temperature detection unit. And a signal generator.

  As described above, according to the present invention, it is possible to achieve further noise reduction in the jet generating device that generates the composite jet.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a jet flow generating apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the jet flow generating device shown in FIG.

  The jet flow generator 10 includes a housing 1, a nozzle body 2 attached to the housing 1, and a vibration actuator 15 disposed in the housing 1. The nozzle body 2 is mounted on the front surface 1a of the housing 1, and a plurality of air flow paths 2a are provided in the upper stage, and a plurality of air flow paths 2b are provided in the lower stage.

  As shown in FIG. 2, the housing 1 is provided with a vibration actuator 15 having a vibration plate 33, a driving device 35, and an elastic support member 36. The elastic support member 36 is attached to the inner wall of the housing 1 and elastically supports the periphery of the diaphragm 33. The inside of the housing 1 is divided into two by the diaphragm 33 and the elastic support member 36, and the chambers 3 and 4 are formed. The chamber 3 formed in the upper part communicates with the outside of the housing 1 through the flow path 2a, and the chamber 4 formed in the lower part communicates with the outside of the housing 1 through the flow path 2b. Yes.

  The drive device 35 is disposed, for example, in the upper chamber 3. For example, a magnet 27 magnetized in the vibration direction R of the diaphragm 33 is built inside the cylindrical yoke 26, and a disk-shaped yoke 34 is attached to the magnet 27, for example. The magnet 27 and the yokes 26 and 34 constitute a magnetic circuit. A coil bobbin 29 around which a coil 28 is wound enters and leaves the space between the magnet 27 and the yoke 26. The coil bobbin 29 is fixed to the surface of the diaphragm 33. By supplying an electrical signal from the drive signal generator 5 (drive signal generator) to the drive device 35 configured as described above, the diaphragm 33 can be vibrated in the direction of the arrow R.

  The diaphragm 33 is made of, for example, resin, paper, or metal. In particular, when the diaphragm 33 is made of paper, the weight is very reduced. Paper is not as easy to make in an arbitrary shape as resin, but it is advantageous in reducing the weight. When the diaphragm 33 is a resin, it can be easily formed into an arbitrary shape by molding. On the other hand, when the diaphragm 33 is a metal, it is made of, for example, copper, aluminum, or stainless steel. Alternatively, magnesium may be used. Magnesium is advantageous because it is lightweight and can be injection molded. The diaphragm 33 may not be a flat plate, and may be, for example, a three-dimensional vibrator. The planar shape of the diaphragm 33 (the shape of the surface substantially perpendicular to the vibration direction R) may be a circle, an ellipse, a rectangle, or a combination thereof.

  The housing 1 is made of, for example, resin, rubber, or metal. Resin and rubber are easy to produce by molding and are suitable for mass production. Further, when the housing 1 is made of resin or rubber, it is possible to suppress sound generated by driving the vibration actuator 15 or airflow sound generated by vibration of the vibration plate 33. That is, when the housing 1 is made of resin or rubber, the attenuation rate of those sounds also increases, and noise can be suppressed. Furthermore, it can respond to weight reduction and becomes low-cost. When the housing 1 is manufactured by injection molding of resin or the like, it can be molded integrally with the nozzle body 2. However, as shown in FIGS. 1 and 2, the jet flow generating device 10 can be easily manufactured when the casing 1 and the nozzle body 2 are separate. When the housing 1 is made of a material having high thermal conductivity, for example, metal, heat generated from the driving device 35 can be released to the housing 1 and radiated to the outside of the housing 1. Examples of the metal include aluminum and copper. When considering thermal conductivity, carbon is not limited to metal. As the metal, magnesium that can be injection-molded can be used. When the leakage magnetic field from the magnetic circuit of the driving device 35 affects other devices of the device, it is necessary to devise a method for eliminating the leakage magnetic field. One of them is to make the housing 1 from a magnetic material such as iron. Thereby, the leakage magnetic field is reduced to a considerable level. Further, it may be a ceramic case for use at high temperatures or for special applications.

  The elastic support member 36 is made of, for example, rubber or resin. The shape of the elastic support member 36 depends on the shape (outer shape) of the diaphragm 33. As shown in FIG. 2, the elastic support member 36 has a cross-sectional shape having one peak and one valley. Hereinafter, this is referred to as a two-roll type elastic support member. In the case of an elastic support member consisting of only one trough or only one crest, the height in the vertical direction in FIG. 2 increases and the thickness increases. When there are a plurality of crests and troughs, complicated movements other than the vibration direction R may occur when the diaphragm 33 vibrates, which may reduce efficiency. Moreover, there is a risk that noise will increase. Therefore, it is desirable to use a two-roll type elastic support member. However, the 2-roll type does not necessarily have to be used.

  The operation of the jet flow generating device 10 configured as described above will be described.

  When, for example, a sinusoidal AC voltage is applied to the drive device 35, the diaphragm 33 performs sinusoidal vibration. Thereby, the volume in the chambers 3 and 4 increases or decreases. As the volumes of the chambers 3 and 4 change, the pressures in the chambers 3 and 4 alternately increase and decrease, and along with this, they are discharged alternately as pulsating flows through the flow paths 2a and 2b, respectively. When air is discharged from the flow paths 2a and 2b, the air pressure around the casing 1 and the nozzle body 2 is reduced, so that the surrounding air is caught in the air discharged from the flow paths 2a and 2b, and is synthesized. A jet is generated. This synthetic jet can be cooled by being blown to a heating element (not shown) or a high-heat part. Examples of the heating element include an electronic component such as an IC, a coil, and a resistor, or a heat radiating fin (heat sink). However, the heating element is not limited thereto, and any heating element may be used.

  On the other hand, when air is discharged from the flow paths 2a and 2b, noise due to airflow noise is generated independently of the flow paths 2a and 2b. However, since each sound wave generated in each flow path 2a and 2b is an anti-phase sound wave, it is weakened mutually. Thereby, noise can be suppressed to some extent, and noise reduction can be achieved.

  FIG. 3A is a graph showing a waveform of a driving signal for driving the driving device 35 and an ideal amplitude waveform of the diaphragm 33 that vibrates by the driving signal. As shown in this graph, when the waveform of a drive signal for driving the drive device 35 (hereinafter sometimes simply referred to as a drive waveform) is, for example, a sine wave, the amplitude waveform of the diaphragm 33 (hereinafter simply referred to as “sine wave”). In some cases, it may be referred to as an amplitude waveform).

  However, in practice, the amplitude waveform is, for example, as shown in FIG. 3B, the amplitude center is the initial position of the diaphragm 33 (the position when the diaphragm 33 is stationary). Often referred to as "origin position") and distorted. In the example shown in FIG. 3B, the waveform is also distorted. The cause of the distortion is that the shape of the driving device 35 and the elastic support member 36 is asymmetric. Alternatively, for example, there is a difference in how the drive device 35 moves due to the difference in the influence of gravity between the case where the drive device 35 is arranged on the chamber 3 side and the case where the drive device 35 is arranged on the chamber 4 side. One of them.

  For example, as shown in FIG. 4A, when the amplitude center of the diaphragm 33 and the origin position are shifted, the amplitude waveform 22 is driven so as to become a sine wave 23 as shown in FIG. Waveform (basic frequency signal (hereinafter referred to as fundamental wave signal)) 20 is corrected. Specifically, in the example of FIG. 4A, the amplitude of one (upward direction) of the amplitude waveform 22 is larger than the amplitude of the other (downward direction), so the drive waveform 21 of FIG. In this way, correction is performed so that one (upward) amplitude is smaller than the other (downward) amplitude. That is, the corrected correction wave signal 21 is a signal obtained by shifting the fundamental wave signal 20 by a predetermined level downward. Thereby, the origin position of the diaphragm 33 and the amplitude center position are the same, and the amplitude can be symmetric with respect to the origin position. As a result, since the wind speed in the flow path 2a and the wind speed in the flow path 2b are substantially equal, the noise levels from both the flow paths 2a and 2b are substantially equal, and noise is reduced.

  Alternatively, for example, as shown in FIG. 5A, when the amplitude waveform 42 is distorted, the drive waveform is changed so that the amplitude waveform becomes a sine wave 23 as shown in FIG. A correction wave signal 41 that gives distortion may be generated. Thereby, the distortion of the amplitude waveform 42 can be canceled out, and in particular, noise due to harmonics can be reduced.

  As shown in FIG. 3B, when both the amplitude center and the waveform distortion occur, a drive waveform that combines FIGS. 4B and 5B may be generated.

  6 and 7 are block diagrams showing the configuration of a processing circuit (corrected wave signal generator) for generating a corrected drive signal. Note that these processing circuits correspond to the drive signal generator 5 described above.

  The analog processing circuit 16 shown in FIG. 6 includes a fundamental wave signal generation circuit 11 that generates a fundamental wave signal, a waveform correction circuit 12 that corrects the fundamental wave signal, and a current amplification circuit 13 that amplifies the corrected signal current. The current-amplified drive signal is output to the vibration actuator 15. The fundamental wave is not limited to the sine wave, but may be a triangular wave, a rectangular wave, or the like. Here, only the fact that the fundamental wave may be a triangular wave, a rectangular wave, or the like is described, and it does not mean that a triangular wave or the like is generated as a correction wave signal as described in FIG. The waveform correction circuit 12 includes, for example, an analog filter, an amplitude gain, an offset adjustment circuit, and the like, but is not limited thereto.

  The digital processing circuit 17 shown in FIG. 7 includes a correction wave signal generation circuit 14 and a current amplification circuit 13 that generate a signal corrected in advance. The current is amplified and output to the vibration actuator 15. The correction wave signal generation circuit 14 may have, for example, a memory such as a ROM (Read Only Memory) storing a data bit string of a drive waveform signal corrected in advance, a D / A (digital / analog) converter, and the like. . The digital processing circuit 17 is excellent in terms of the scale of the additional circuit and the diversity of correction.

  6 or 7, a voltage amplifier circuit may be used instead of the current amplifier circuit 13.

  The analog processing circuit 16 or the digital processing circuit 17 is more realistic as an IC. In particular, these processing circuits 16 or 17 have two functions of a signal generation unit and a current amplification unit, but these can be integrated into one IC.

  As described above, in the present embodiment, a correction wave signal in which the fundamental wave signal is corrected is generated, and the diaphragm 33 is driven by this correction wave signal, so that the amplitude waveform of the diaphragm 33 has an appropriate shape. Thus, further noise reduction can be realized.

  FIG. 8 is a graph showing an amplitude waveform of the diaphragm 33 according to another embodiment of the present invention. As shown in the figure, not only the amplitude waveform 43 of the sine wave but also the drive signal is generated (the fundamental wave signal is corrected) so that the amplitude waveform 44 is a mixture of a sine wave and a rectangular wave (or trapezoidal wave). Also good. In this amplitude waveform 44, the maximum in the positive direction and the negative direction is smaller than the amplitude waveform 43 of the sine wave, for example, a maximum value of about 90% of the amplitude waveform 43. However, the acceleration reaching the maximum of the amplitude waveform 44 is larger than that of the amplitude waveform 43. For example, the maximum in both positive and negative directions of the amplitude waveform 44 is linear.

  According to such an amplitude waveform 43, since the amplitude can be suppressed, vibration generated in the entire jet flow generating device 10 due to vibration of the diaphragm 33 can be suppressed. Even if the amplitude is suppressed, the acceleration is larger than the amplitude waveform 43, and accordingly, the wind speed of the air from the flow paths 2a and 2b is equivalent to that of the amplitude waveform 43, and the heat dissipation efficiency is lowered. There is no. Further, since the amplitude can be reduced, the thickness of the casing 1 of the jet flow generating device 10 (the thickness of the casing 1 in the vibration direction of the diaphragm 33) can be reduced.

  The amplitude waveform 43 can also be realized by the processing circuit 16 or 17 shown in FIG. 6 or FIG. The amplitude waveform by the corrected drive signal may have various shapes, and a form in which at least two of a sine wave, a triangular wave, a rectangular wave, and a trapezoidal wave are combined may be considered.

  FIG. 9 is a diagram according to still another embodiment of the present invention, and shows a mode in which a control signal can be externally added to the processing circuit 16 or 17 as shown in FIG. 6 or FIG. . The signal generation circuit 19 is a circuit that generates a corrected correction wave signal, such as the fundamental wave signal generation circuit 11, the waveform correction circuit 12, and the correction wave signal generation circuit 14 as described above. The control signal includes an amplitude control signal and a frequency control signal. The control signal can be generated by an electronic device (not shown) on which the jet flow generating device 10 is mounted, for example. According to such a configuration, it is possible to control to the optimum thermal resistance performance in accordance with the heat generation amount of the electronic device.

  FIG. 10 is a diagram according to still another embodiment of the present invention, and shows an example in which a plurality of jet flow generators 10 are used. The jet generators 10a to 10c of the system 50 include signal generation circuits 19a, 19b, 19c such as the fundamental wave signal generation circuit 11, the waveform correction circuit 12, and the correction wave signal generation circuit 14 described above, selectors 46a, 46b, 46c, Current amplifier circuits 13a, 13b, 13c and vibration actuators 15a, 15b, 15c are provided, respectively. Each of the jet flow generating devices 10b and 10c includes an interface for inputting the signal 47 output from the signal generating circuit 19a. “Interface” is, for example, a connection terminal, but is a broad concept that includes software in addition to the connection terminal.

  The selector 46b switches between the input signal from the signal generation circuit 19b and the external input signal 47. Similarly, the selector 46c switches between the input signal from the signal generation circuit 19c and the external input signal 47. The jet generator 10a is also provided with an external input interface and selector 46a similar to the jet generators 10b and 10c, and these jet generators 10a to 10c are jet generators having the same function. When the jet generating device is used alone, the selector selects a signal from a signal generating circuit included in the jet generating device. When n (n is 2 or more) jet flow generators are used in combination, (n-1) selectors select an external input signal.

  According to the configuration as shown in FIG. 10, not only can the jet generators 10a, 10b and 10c be used alone, but by combining them, all the vibration actuators 15a are driven by one signal generating circuit. It becomes possible to do. Moreover, the vibration which arises in one jet generating device itself can be canceled by combining several jet generating devices. Furthermore, noise can be reduced by phase control of the plurality of vibration actuators 15.

  In the embodiment shown in FIG. 10, the signal generation circuits 19a, 19b, and 19c do not necessarily have to be a circuit that generates a correction wave signal obtained by correcting a fundamental wave signal, and may simply be a circuit that generates a fundamental wave signal. . The gist of the apparatus according to the embodiment of FIG. 10 is that each jet generating apparatus is provided with an external input interface for taking in a drive signal from the outside.

  FIG. 11 shows still another embodiment of the jet flow generator. The jet generating device 30 includes a single signal generating circuit 19, a plurality of current amplifying circuits 13 for inputting signals output from the signal generating circuit 19, and a drive signal from each current amplifying circuit 13. A plurality of vibration actuators 15 to be driven are provided. According to such a configuration, the plurality of vibration actuators 15 can be operated in synchronization with one signal generation circuit 19.

  FIG. 12 is a perspective view showing a state in which the jet flow generating device 10 and the like shown in the above drawings are mounted on the PC 150 as an electronic device. The synthetic jet supplied from the jet generating device 10 is blown onto the heat sink 146, and air with heat is discharged from the exhaust port 151 of the PC housing provided behind the heat sink 146.

  In FIG. 12, a laptop PC is used as an example of the electronic device, but a desktop PC may be used. Not only a PC but also a PDA (Personal Digital Assistance), an electronic dictionary, a camera, a display device, an audio / visual device, a projector, a mobile phone, a game device, a car navigation device, a robot device, and other electrical appliances.

  FIG. 13 is a diagram illustrating an example of measurement results regarding the relationship between the amplitude of the diaphragm 33 and noise. As can be seen from this figure, it can be seen that the noise tends to increase when the noise is large at the time when the amplitude becomes zero, that is, when the speed is large.

  Therefore, consider a case where the vibration pattern of the diaphragm 33 is not a sine wave but a triangular wave. FIG. 14 is a graph showing an example of a plurality of amplitude waveforms of the diaphragm 33. In FIG. 14, a thin broken line is a sine wave, a thick solid line is a triangular wave, a thin solid line is a waveform in which the peak of the triangular wave is blunted, for example, as a quartic function curve (regardless of the amplitude scale), and a thick broken line is the waveform 40. A waveform in which the peak value is matched with the peak value of the triangular wave 39 (hereinafter, this waveform is referred to as “triangular wave + quadratic curve wave”) is shown. In FIG. 14, the amplitude of the vertical axis is normalized to ± 1 for the maximum and minimum peak values of the sine wave 37.

  FIG. 15 is a graph showing the speed of each sine wave 37, triangular wave 38, triangular wave + quadratic function curve wave 39 shown in FIG. Reference numerals 37a, 38a, and 39a respectively indicate. FIG. 16 is a graph showing the acceleration of each of the waveforms 37 to 39 shown in FIG. Reference numerals 37b, 38b, and 39b respectively indicate.

  In the case of the triangular wave 38, the velocity component 38a of the motion has a peak value as small as 64% as compared with a sine wave having the same amplitude as shown in FIG. However, since the change in speed is large at the peak time (phase of 90 degrees or 270 degrees), the acceleration 38b that is the differential of the speed needs to be increased rapidly as shown in FIG. The design of the vibration actuator 15 that realizes such a motion is not realistic. Accordingly, a mode in which the increase in acceleration is suppressed by partially replacing the vicinity of the peak of the triangular wave 38 with a curve (for example, a quadratic or higher order function) in the motion pattern of the diaphragm 33 will be considered. This is a triangular wave + quartic function curve wave 39.

  Specifically, in this embodiment, the contact point between the peak of the triangular wave 38 and a certain quadratic function curve is (p1, p2). “Near the peak” means p1 to p2. p1 to p2 is, for example, 30 to 150 degrees, but is not limited to this range, and can be set as appropriate, for example, 40 to 140 degrees, 60 to 120 degrees, and the like.

Here, the triangular wave 38 shown in FIG. 14 is assumed to be a function T (p), and in this T (p), the section corresponding to the phases p1 to p2 is replaced with, for example, a quartic function y (p).
y '(p1) = T' (p1) (1)
y '(p2) = T' (p2) (2)
y '' (p1) = T '' (p1) = 0 (3)
y '' (p2) = T '' (p2) = 0 (4)
y '''(90 degrees) = 0 ... (5)
From these five conditions, it is possible to calculate a term necessary for expressing the quartic function y (p). Equations (1) and (2) are speed conditions. Expressions (3) and (4) are acceleration conditions. In the case of the triangular wave 38, the acceleration is zero except in the vicinity of the apex, and therefore equations (3) and (4) are established.

  However, if the peak of the triangular wave 38 is simply replaced with a quartic function curve, the amplitude peak value becomes smaller than the original triangular wave 38 as shown by the waveform 40 in FIG. There is. For example, an appropriate coefficient may be applied to the waveform 40. The triangular wave + quartic function curve wave 39 generated in this way looks like a waveform that is relatively similar to the sine wave 37 in FIG. 14 showing the amplitude component, but in FIG. 15 showing the velocity component, the triangular wave + quartic function curve 39 It can be seen that the velocity peak value of the wave 39a falls between the sine wave 37a and the triangular wave 38a.

  Thus, the amplitude of the diaphragm 33 is driven by the sine wave 37 when the diaphragm 33 is driven by the triangular wave + quadratic function curve wave 39 which is a waveform in which the peak value of the triangular wave is blunted. Even in the same case, the peak value of the speed of the diaphragm 33 can be lowered.

  However, in FIG. 16 showing the acceleration component, the peak value of the acceleration of the triangular wave + quadratic function curve wave 39b is larger than the peak value of the sine wave 37b. Therefore, in designing, it is necessary to give an optimum parameter for the range (p1, p2) to be replaced with a quartic function curve so that the performance and vibration specifications of the vibration actuator 15 are acceptable and the noise is reduced. There is.

  On the other hand, when the noise is minimized due to the asymmetric structure of the casing 1 of the jet flow generator 10 and the chambers 3 and 4 and the nonlinearity of the rigidity of the elastic support member 36, vibrations It is conceivable that the maximum peak value and the minimum peak value of the plate speed may be different. Therefore, consider the motion pattern of the diaphragm 33 based on the sawtooth wave 58 as shown in FIG. 17 instead of the triangular wave 38.

  While the phase of the triangular wave 38 rises from zero to 90 degrees while the amplitude rises from zero to the maximum value, the phase change in the sawtooth wave 58 is from 0 degree to an arbitrary pc degree. That is, the difference between the triangular wave 38 and the sawtooth wave 58 is that the triangular wave 38 has the same rising and falling slopes of the signal, and the sawtooth wave 58 has a different slope. In the sawtooth wave 58, since the rising and falling slopes of the signal are different, the speed peak value of the diaphragm 33 is different between the maximum peak value and the minimum peak value as shown in the example of the speed component in FIG. . In addition, in this example, when the point that defines the “near peak” for generating the quartic function curve of the sawtooth wave 58 is (p1, p2) as in FIG. 14, in this example, the phase between p1 and pc is Is longer than the phase between pc-p2.

  Similarly to the case of the triangular wave shown in FIGS. 14 to 16, as shown in FIG. 19, since the acceleration component 58 b of the sawtooth wave is steep and large if the sawtooth wave 58 remains as it is, the vicinity of the peak of the sawtooth wave 58 is observed. Replace with a quartic function curve. In this case, similarly to the triangular wave 38 described above, y ′ (p1) = T ′ (p1), y ′ (p2) = T ′ (p2), y ″ (p1) = T ″ (p1) = 0 , Y '' (p2) = T '' (p2) = 0, y '' '(pc) = 0, it is possible to calculate the terms necessary for the expression of the quartic function y (p) Become. As shown in FIG. 17, the diaphragm 33 is driven by the sawtooth wave + quartic function curve wave 59 generated in this way (the sawtooth wave quaternary function curve wave irrelevant to the amplitude scale is indicated by reference numeral 60). The Thereby, the noise and the peak velocity due to the structure in the casing 1 of the jet flow generating device 10 and the chambers 3 and 4 being asymmetrical and the nonlinearity of the rigidity of the elastic support member 36 are observed. Noise due to the increase can be reduced.

  Here, the triangular wave + quartic function curve wave 39 or the sawtooth wave + quartic function curve wave 59 is generated by correcting the fundamental wave signal (for example, sine wave signal) in the waveform correction circuit 12 shown in FIG. Alternatively, a configuration in which the signal generated in advance by the correction wave signal generation circuit 14 in FIG. 7 is stored is conceivable.

  FIG. 19 is a table showing noise measurement results of the jet flow generating device 10 when the same diaphragm 33 is driven by a sine wave 37, a triangular wave + quadratic function curve wave 39, and a sawtooth wave + quartic function curve wave 59, respectively. . From this, it can be seen that the noise can be suppressed when driven by the triangular wave + quadratic function curve wave 39 and further by the sawtooth wave + quartic function curve wave 59 than when driven by the sine wave 37. FIG. 20 is a graph showing each noise spectrum of a sine wave, a triangular wave + quadratic function curve wave, and a sawtooth wave + quartic function curve wave. The change of the noise level due to the movement pattern can be seen from the change of the noise peak values located at 1 kHz to 1.8 kHz and 6 kHz shown in FIG.

  Next, a control device for a jet flow generating device according to an embodiment of the present invention will be described.

  FIG. 21 is a block diagram showing the configuration of the vibration control device of the jet flow generating apparatus as an example. The control device 70 of the jet flow generator includes a vibration actuator 15 having a diaphragm 33 and a drive device 35, a signal generator 53 that generates a drive signal for the vibration actuator 15, and a voltage of a signal output from the signal generator 53. An amplifying unit 54 for amplifying current or power, a motion state detecting unit 51 for detecting the motion state of the diaphragm 33, and a control unit for causing the signal generating unit 53 to generate a predetermined signal based on a detection signal from the motion state detecting unit 51 52.

  Examples of the motion state detection unit 51 include a non-contact optical sensor and a magnetic sensor that detect the displacement of the diaphragm 33. However, the present invention is not limited thereto, and a speed sensor, an acceleration sensor, or the like that is attached to the diaphragm 33 and used may be used. In the case of the optical sensor, for example, a reflective optical sensor may be installed on the ceiling surface of the casing 1 of the chamber 3 and the floor surface of the casing 1 in the chamber 4 of the jet flow generating device 10 shown in FIG. . Thereby, the displacement of the diaphragm 33 in the vertical direction can be detected.

  The signal generation unit 53 includes, for example, the fundamental wave signal generation circuit 11 and the waveform correction circuit 12 illustrated in FIG. Or the signal generation part 53 is comprised by the correction wave signal generation circuit shown in FIG.

  In this control device 70, for example, when the motion state detection unit 51 detects that the motion state of the diaphragm 33 is a waveform like the amplitude waveform 22 of FIG. The correction waveform signal 21 shown in FIG. 4 (B) is output as a drive signal. In this case, the control unit 52 compares the waveform 22 (see FIG. 4A) detected by the motion state detection unit 51 with the waveform 20 of the target value sequentially in real time so that the deviation becomes zero. The signal generator 53 is controlled to generate the drive signal 21 shown in FIG. Alternatively, when the motion state detection unit 51 detects that the motion state of the diaphragm 33 is a waveform such as the amplitude waveform 42 in FIG. 5A, the signal generation unit 53 displays the waveform in FIG. The correction waveform signal 41 shown is output as a drive signal. In this case, the control unit 52 compares the waveform 42 (see FIG. 5A) detected by the motion state detection unit 51 with the target value (the waveform 20 in FIG. 5A) sequentially in real time. Control is performed so that the signal generator 53 outputs the drive signal 41 in FIG. 5B so that the deviation becomes zero. Of course, the control device 70 is not limited to the configurations shown in FIGS. 4B and 5B.

  Through the feedback control as described above, the diaphragm 33 can be driven by generating a drive signal having an arbitrary pattern according to the motion state of the diaphragm 33. As a result, it is possible to suppress variations in air blowing performance, noise specifications, vibration specifications, and the like during manufacturing for each of the plurality of jet flow generating devices 10.

  For the feedback control as described above, it is particularly preferable to use the analog processing circuit 16 shown in FIG. However, in the case where the digital processing circuit 17 shown in FIG. 7 is used, the control unit prepares several types of correction wave signals in advance. The digital processing circuit 17 is controlled so that a correction wave signal that is close is selected.

  In the present embodiment, not only feedback control but also feedforward control is possible. For example, the control unit 52 temporarily stores the waveform 22 of FIG. 4A or the waveform 42 of FIG. 5A as a detection signal of the motion state detection unit 51 for a predetermined period in a memory (not shown). Based on the stored waveform, the signal generator 53 generates a correction wave signal. This memory may be a memory in the control unit 52 or an external memory accessible by the control unit 52. Then, after the correction wave signal is generated, the control unit 52 may output the correction wave signal as a drive signal in an open loop. Various timings can be considered for the timing corrected by the signal generator 53. For example, the timing may be a periodic timing, or may be a timing such as once or a plurality of times immediately after the jet flow generator 10 is turned on. Alternatively, other timing may be used.

  FIG. 22 is a modification of the form shown in FIG. The control device 80 includes a detection unit 55 including a temperature sensor 61 and / or a detector 62 that detects an external signal as a detection unit. When the temperature sensor 61 is used, the control unit 52 includes a temperature around the jet flow generating device, for example, a temperature around the casing 1, a temperature of a heating element to which the jet is applied, or the like, The atmosphere around the jet flow generating device, the temperature of the components, and the like are input as detection signals. Based on this detection signal, the control unit 52 controls the amplification degree by the amplification unit 54 to change the amplitude of the diaphragm 33 or the signal generation unit 53 to change the drive frequency. As a result, the air volume of the jet flow generator is varied, and optimal temperature control is possible.

  Further, as the detector 62 that detects an external signal, for example, when there is a host control unit (not shown) other than the control unit 52, a receiving unit that receives a signal from the host control unit may be considered. In this case, it is assumed that the jet flow generating device is mounted on an electronic device such as a PC. Further, when the jet flow generating device is mounted on an electronic device, even if the motion state detecting unit 51 (see FIG. 21) or the temperature sensor 61 is not mounted on the jet flow generating device, these motion state detecting units are mounted on the electronic device. A configuration in which 51 and a temperature sensor 61 are mounted is also conceivable.

  FIG. 23 shows an example in which the form shown in FIG. 21 is combined with the form shown in FIG. That is, the control device 90 includes a motion state detection unit 51 that detects the motion state of the diaphragm 33 and a detection unit 55 that detects the temperature and / or an external signal. According to such a configuration, it is possible to drive the diaphragm optimally according to the configuration of each component of the jet flow generating device and the environment around the jet flow generating device.

  The present invention is not limited to the embodiment described above, and various modifications are possible.

  For example, in the embodiment shown in FIG. 21 and the like, the waveform that is the target of the amplitude of the diaphragm 33 has been described as the sine wave 23 in FIGS. 4 (A) and 5 (A). However, the target waveform of the amplitude of the diaphragm 33 in this case may be the triangular wave + quadratic function curve wave 39 or the sawtooth wave + quartic function curve wave 59 shown in FIG.

It is a perspective view which shows the jet flow generator which concerns on one embodiment of this invention. It is sectional drawing of the jet flow generator shown in FIG. FIG. 3A is a graph showing a waveform of a driving signal for driving the driving device and an ideal amplitude waveform of the diaphragm that vibrates by the driving signal. FIG. 3B is a graph showing an example in which distortion occurs in the amplitude waveform of the diaphragm. FIG. 4A is a graph showing an example in which distortion occurs in the amplitude waveform of the diaphragm, and shows a form in which the center of the amplitude and the origin position are deviated. FIG. 4B is a graph when the drive waveform of FIG. 4A is corrected. FIG. 5A is a graph showing an example in which distortion occurs in the amplitude waveform of the diaphragm. FIG. 5B is a graph when the drive waveform in FIG. 5A is corrected. It is a block diagram showing a processing circuit for generating a corrected drive signal. FIG. 6 is a block diagram illustrating a processing circuit according to another embodiment for generating a corrected drive signal. It is a graph which shows the amplitude waveform of the diaphragm based on other embodiment of this invention. It is a block diagram which shows the form which can add a control signal to the processing circuit as shown in FIG. 6 or FIG. 7 from the outside. It is a block diagram which shows the example in which multiple jet flow generators are used. It is a block diagram which shows another embodiment of a jet flow generator. It is a perspective view which shows the state by which the jet flow generator shown to each said figure was mounted in PC as an electronic device. It is a figure which shows the example of the measurement result about the relationship between the amplitude of a diaphragm, and noise. It is a graph which shows the example of the several amplitude waveform of a diaphragm, and shows the example of a triangular wave especially. It is a graph which shows each speed of a sine wave, a triangular wave, a triangular wave + quartic function curve wave shown in FIG. It is a graph which shows each acceleration of a sine wave, a triangular wave, a triangular wave + quartic function curve wave shown in FIG. It is a graph which shows the example of the several amplitude waveform of a diaphragm, and shows the example of a sawtooth wave especially. It is a graph which shows each speed of the sine wave, sawtooth wave, sawtooth wave + quartic function curve wave shown in FIG. It is a graph which shows each acceleration of a sine wave, sawtooth wave, sawtooth wave + quartic function curve wave shown in FIG. It is a graph shown in each noise spectrum of a sine wave, a triangular wave + quartic function curve wave, and a sawtooth wave + quartic function curve wave. It is a block diagram which shows the structure of the control apparatus of a jet flow generator. It is a block diagram which shows the modification of the form shown in FIG. It is a block diagram which shows the example which combined the form shown in FIG. 21, and the form shown in FIG.

Explanation of symbols

3, 4 ... Chamber 10, 10a-10c, 30 ... Jet generator,
DESCRIPTION OF SYMBOLS 11 ... Fundamental wave signal generation circuit 12 ... Waveform correction circuit 14 ... Correction wave signal generation circuit 15 ... Vibration actuator 16 ... Analog processing circuit 17 ... Digital processing circuit 19, 19a-19c ... Signal generation circuit 33 ... Diaphragm 35 ... Drive device 38 ... Triangular wave 39 ... Triangular wave + quadratic function curve wave 46a-46c ... Selector 58 ... Saw wave 59 ... Saw wave + quartic function curve wave 70, 80, 90 ... Control device 146 ... Heat sink 150 ... PC

Claims (10)

A plurality of chambers each having an opening and containing a gas;
A vibrator that alternately discharges the gas as a pulsating flow through the openings by applying a pressure change to the gas contained in the chambers;
A correction wave signal generator for generating a correction wave signal in which a fundamental wave signal for driving the vibrating body is corrected ;
When the vibrating body is driven by the fundamental wave signal, when the amplitude center of the vibrating body is shifted from the origin position which is the initial position of the vibrating body, the correction wave signal generator A jet that generates, as the correction wave signal, a drive signal formed such that the amplitude in one direction is different from the amplitude in the opposite direction to the one so that the center of amplitude of the vibrating body and the origin position are the same. Generator. The jet generator according to claim 1,
The correction wave signal generator is
A fundamental wave signal generating circuit for generating the fundamental wave signal;
And a correction circuit for correcting the fundamental wave signal generated by the fundamental wave signal generation circuit. The jet generator according to claim 1,
The correction wave signal generator includes a correction wave signal generation circuit that generates a correction wave signal corrected in advance. The jet generator according to claim 1,
The correction wave signal generator generates a drive signal in which amplitude waveform distortion is corrected as the correction wave signal. The jet generator according to claim 1,
The correction wave signal generator corrects the fundamental wave signal so that the amplitude waveform of the vibrator becomes an amplitude waveform obtained by combining at least two of a sine wave, a triangular wave, a rectangular wave, and a trapezoidal wave. . The jet generator according to claim 1,
The correction wave signal generator generates, as the correction wave signal, a drive signal corrected so as to blunt the peak of a triangular wave. The jet generator according to claim 6 ,
The correction wave signal generator generates the drive signal as a correction wave signal corrected in advance. The jet generator according to claim 6 ,
The correction wave signal generator generates, as the correction wave signal, a drive signal corrected so as to blunt the peak of the sawtooth wave. The jet generator according to claim 8 ,
The correction wave signal generator generates the drive signal as a correction wave signal corrected in advance. The jet generator according to claim 1,
A plurality of the jet flow generating devices are provided,
Of the plurality of jet generators, the first jet generator has the correction wave signal generator,
Of the plurality of jet generating devices, a second jet generating device inputs an external input interface for inputting a first drive signal of the vibrating body from the outside of the first jet generating device, and a second of the vibrating body. A jet flow generator, comprising: a second correction wave signal generator that generates a drive signal for the first correction signal; and a selector that selects one of the first and second drive signals.